Method of and means for transferring loose bulk material



May 10, 1938. L, F, HOLLY 2,116,603

METHOD OF AND MEANS FOR TRANSFERRING LOOSE BULK MATERIAL Filed Aug. 26,1953 2 Sheets-Sheet 1 &

Luau 10E HnLLY INVENTOR.

- ATTORNEYS.

May 10,- 1938. L, F. HOLLY 2,116,603

METHOD OF AND MEANS FOR TRANSFERRING LOOSE BULK MATERIAL Filed Aug. 26,1953 2 Sheets-Sheet 2 52 s1 47 4s 38 '9 35 so as v 2 a Q l a M 9 f 39'32 f 1 22 m LUDWIGFHULLY INVENTOR.

ATTORNEYS.

Patented May 10,1938 a 1 2,116,603

UNITED STATES PATENT OFFICE METHOD OF AND MEAN S FOR TRANS- FERRINGLOOSE BULK MATERIAL Ludwig F. Holly, Madison, N. J. Application August26, 1933, Serial No. 686,885 16 Claims. (01. 214-83) This inventionrelates to amethod of and means origin to the railroad, or for thetransfer from for the transfer of loose bulk material. More that pointof origin to the point of ultimate particularly thisinvention relates tothe transfer destination. 7 of such material between unflxed, varyingpoints; Likewise the means of my invention, as illusat the same time itconcerns transfer between trated in the following by specific examples,are points where for that reason or on account of not to be limited tothe showing of the drawings distance a permanent, fixed conveying systemis but the protection of this patent is to extend to not feasible.adaptations thereof within the ordinary skill of On the other hand Iintend to bring about by engineers and manufacturers.

this novel transfer method and means the fiexibil- In the drawings: 10ity indicated above together with the utmost ex- Fig. 1 shows a sideview of a truck on which a pedieney, economy of operation andmaintenance means of my invention is accommodated. at a very modestoriginal cost of equipment. Fig. 2 shows a sectional end view of saidmeans This may be best explained by referring to extaken at the rear ofa truck.

amples and by comparison to the prior art. It Fig. 3 shows a detailedtop view illustrating the 15 has been customary to transfer loose bulkmaoperation of a sliding false bottom forming part terial, from freightcars for instance to an inof my invention. I

dustrial plant, or other point of destination at a Figs. iand 5illustrate in a sectional side view certain distance from the railroadsiding, by and in a rear view, respectively, a modification transferringthe bulk material, say flour, cement of my invention. 20 or malt, inbarrels or bags which are stacked in Figs. 6'and '7 serve to illustratethe method of the freight car, into a truck and tounload thismyinvention by views taken at the point where material in the samemanner. at the other end, the bulk is transferred to a vehicle of myinvenwhere it then may be removed from the bags or thin and at a pointwhere it is delivered therefrom, 26 barrels and be placed into acollective storage respectively. container. Fig. 8 shows a sectionalview of the container This necessitates of course that the material ofFig. 1, illustrating in particular the-electric arbe placed into bags orbarrels at the original rangements and the operation of the slidingfalse point of shipment where it is placed into the bottom. Inconnection therewith the said figure freight car. shows an exemplarywiring diagram. 30

Such underdivided handling is overcome by my Fig. 9 is a sectionalbottom view of a modified invention, which does not -make it necessaryto bottom slide of my invention. handle the material in parcels but itmay be Fig. 10 shows a side view of acontainerin which loosely pouredand filled into a freight car. At the modified slide of Fig. 9 is used;part of the the intermediate railroad siding, from which it is wall ofthe container and of a trough below is 35 to be transferred to theultimate pointof destinasectioned away.

tion, the material is transferred from the freight Similar numeralsrefer to similar parts throughcar in a continuous flow into asultable'container out the various views. i on a vehicle whichaccommodates the contents The front part of the truck ll of Fig. 1 isnot '40 of said car in one or several loads, and brings it shown. Behindthe cab I2 is arranged, side by to the ultimate point of destination.The cone side, a prime mover IS, a pump H, and a small tainer is thereagain unloaded, in a continuous electric generator G, the said partsbeing coupled flow, the loose bulk being handled pneumatically to eachother for simultaneous operation: It is throughout, as later ondescribed. of course understood that the power for pro- Another objectof this invention is to grade the pelling the pump and generator may bedirectly 45 loose bulk material during transfer andto protaken from theengine of truck II, that the curvide means for delivering it separately,for inrent supplied by the generator may be supplied stance the finermaterial after the coarser ma from the electrical plant, say the battery01' the terial. t truck, and the suction and compression furnished 00While the foregoing specific example will also by the pump may also besupplied otherwise, from be illustrated in the following description(Figs. an independent source, as well known to en- 6 and 7), theapplication of the method of this gineers. invention' is of course notto be limited thereto, Behind the prime mover the pump and the it mayjust as well be applied in the instance generator,is arranged upon thetruck ll theclosed mentioned above for transfer from the point ofcontainer 2|. At the top in the back of the 55 way of the chamber 22,the loose bulk contained in the container being prevented from passinginto said chamber and therethrough into said pump, by the filter bag 24.

. The filter bags 24 are separated from the space centrally below thechamber 22 by means of a. pair of partitions 25 depending from saidchamber into container 2|. Between said partitions, there is an inlet 26upon the tank which is suitably flanged at its end 21, so that a suctionconduit, for instance a hose 28, may be coupled to the said inlet.

When the loose bulk is to be filled into the container 2|, say from afreight car 29 (Fig. 6) the free end of the said hose 28,-which may beprovided with suitable proportioning means, for instance a suitable feednozzle,-is immersed through a suitable opening of the freight car 29into-the loose bulk container therein. When suction is now applied tothe container 2| in the manner described above, then the loose bulkmaterial in the freight car, into which the free end.

of hose 28 is immersed, streams through said hose and through inlet 26into the container 2| and piles up therein from the left to the right.

I In order to prevent the loose bulk, which is sucked in through inlet26, from damagingthe walls of the container, by force of its impact,

and in order also to distribute the bulk entering upon the container ina preferred way, a bailie 30 isarranged between the partitions 25 in thecontainer, in the path of the loose bulk entering upon the containerthrough the inlet 26.

Underneath the container 2|, and comprised therein, extends a trough 3|Into the said trough issues from the left a conduit 32 which leads-tothe valve 20. At the rear end of the truck, an outlet 33 opens fromtrough 3|. said outlet is provided with aflange 34 similar to the flange21 on inlet 26, so that the hose 28 may be connected to the said outletin the same manner as it is shown in Fig. 1 to be connected to the inlet26 (see Fig. '7). A cap 44 closes the'inor outlet, when hose 28 is notconnected thereto.

Where the trough 3| merges with the sides of the container 2| horizontalsections or flats 35 close the perforations near theedges of a flexibleband 36 (a steel plate for instance) {which slides thereon as }a trapdoor for the container,- and separates'th epontainer from the trough,

when extended all the way to the left in said container.

(Figs. 1 and 8). In the rear of the container there is a smallcompartment 31 just above the trough 3|. Un-

derneath the bottom of the front wall 'of compartment 31 the band 36slidably extends there-v There is a reel accommodating band 36;'

into. or the walls of the compartment 31 are shaped band 36 coils upback into the container, or a spiral 38 may be arranged in the saidcompartment 31 upon which The the band 36 slides into a coiled upposition in said compartment when it is moved back in the container.

Rods 39 extend in the container above the trough transversely theretoand serve to. retain the band-38 in an extended position upon the flats35 when said band extends as a trap door Jbetween the container and thetrough 3| In the compartment 31 pinions 40 engage upon the perforationsof the band 36 in rack and pinion fashion. I'heyare mounted upon a shaft4|. That shaft extends through suitably packed openings in the wall ofcompartment 31 to the outside of the container, where a gear 42 ismounted thereon. A pinion 43 upon the end of motor Mengages upon thegear, so that clockwise rotation (Figs. 1 and 8) of the motor slides themotor M and serve to open or close the circuit thereof in a manner to behereinafter more fully described. It may here be stated that the circuitof the motor M is o ened when=the lever 45 is raised onto the band 3near the end of the closing movement of said band, from the right to theleft so that the counter-clockwise rotation-bf said motor is stoppedwhen the band I fully separates the container 2| from the trough Whenthe trap door is opened again,i. e., whenband 36 slides to the right,thelever 45 slides ofi band 36 into the position in which it is shown inFig. 8. A suitable extension 49 of said lever comes to rest on a lug 50provided upon the inside of container 2| so that the counter clockwisemovement of lever 45 is checked in a position, from which it is againshifted into a position of opening the mercury switch 41, when lateron'the trap door is closed again.

The lever 46 operates and is also provided with an extension, which ismarked 5|, and which engages upon the stationary lug 52 on the wall ofcompartment 31; that happens when the trap door is opened fully,-lever46 sliding oil the end of band 36 and opening the mercury switch 48. Themercury switch 48 opens and closes the part of the circuit of motor M,which controls the opening movement of the trap door.

When thetruck H is loaded with loose bulk material and has reached'thepoint where said load is to be delivered, Valves l1 and 20 are openedand valves l8 and I9 are closed. Cover 44 is placed onto inlet 21,,hose28 is connected to outlet 33 and is extended into a delivery bin(building 53), and pump 4 is started to suck air in through'valve 1,said air passing through alve 20, through trough 3| (the trap door beingclosed) and through hose building 53.

The manner in which the unloading of the ,truck is completelyautomatically controlled, will be described later. This generalexplanation of the unloading Proceeds on the assumption'of anykind ofcontrolled release of the loose bulk material from the container 2| forinstance by in a similar manner 7 28 into the delivery a manualoperation of the plate 36. The latter may be, a solid plate which ismoved back or loose bulk material will begin to flow by gravity out ofthe container 21 through the partly opened trap door into the trough andwill be carried by the air blast into the delivery bin 53.

Should too large a quantity of the loose bulk material drop into thetrough, the trap door may be closed to such an extent as to limit theflowof the loose bulk material into the trough. When the flow of theloose bulk material is too slow,

the trap door may be opened more, and thus eventually the whole contentsof the container 2| are conveyed from the truck 'into the bin 53, the

' transfer from the freight car 29 to an ultimate storage bin thus beingcompleted.

.An alternative means for controlling the delivery of materials from thecontainerinto the delivery building is illustrated by Figs. 4 and 5.This arrangement comprises, in addition to the pump and suctionarrangement of the truck heretofore described,-which are not shown,--and the container and trough 55,-which correspond to the container 21and trough CH of the prior description,a screw conveyor 56, extendingthrough the length of the trough and pro vided with a drive, a motor orcrank for instance which are not shown, and a conduit 51 underneath thetrough and communicating therewith by .way of an opening 58 at the rear.To the end of the conduit 51 the hose 28 may be connected in the mannerdescribed above and the pump discharges the air into the conduit 51.

By rotation of the screw conveyor 56 in a clockwise direction (Fig. 5)fixed quantities of the bulk material are delivered to the opening 58and they are discharged through said opening into the air blast, andthus conveyed into a storage-bin in a manner similar to that exhibitedin'Fig. 7.

The speed at which the screw conveyor 56 is rotated controls thedischarge of the material into the air blast, arid proper procedure ofsuch discharge may-be checked by observing the pressure of the air.preferably at the very entrance of the conduit 51.

The manner in which the air pressure may be observed and may serve tocontrol the delivery of the material from the truck will now bedescribed; aside from gages 59 and 60, which serve to check therarefaction and the compression of the intake and outlet of the pump. Imay provide a suitable gage at the point of entrance of the compressedair into the trough, such a gage being exemplarily indicated by amercury gage Si in the drawings." The gage SI of Fig. 8 connects toconduit 32 at the one end where arrow 32 suggests the entrance ofcompressed air into said gage. Making use of a mercury column in a crudemercury pressure gage, may not be the means which is practical in allinstances for the pressure control of the unloading as it will behereinafter described, but it will sufilce for the purpose of explainingin detail one example of the pressure control of my invention. Manyother types of pressure controlled circuit breakers are known,

and,--pa'rticularly when working between fixed pressure limits,-may herebe substituted.

' trough 3|, underneath container 2i.

acts as follows:-

The trap door is normally closed when the pump is not driving an airblast through the The trap door remains therefore closed as long as themercury gage 6| registers substantially atmospheric pressure or less.When pressure is registered, the trap door is to be opened slowly, andthis slow opening may proceed continuously until the wholeretainer hasbeen emptied.

But it may wellhappen that, in one or the other instance, while the trapdoor is being gradually and continuously opened, too much of the loosebulk material slides into the trough and that not all of it may beremoved instantly by the blast in the trough, as it is desirable for asmooth function of the' device, so that the air cannot freely passthrough and carry the loose material out of the trough into the storagebin.

Under those circumstances,-if the gradual, continuous opening of thetrap door continues,-conditions become worse, until finally the air isnot able to work its way through to the outlet 33 at all. Therefore,instead of continuing to open, the trap door stops in its openingmovement, or it might even be desirable to close it, partly or wholly,so that the air blast is capable of clearing the trough beforeadditional bulk material is released thereinto.

Making use of the pressure gage 6| for that purpose, it will beunderstood that it registers a I very high or highest pressure when thetrough is blocked so that the air blast cannot freely pass therethrough.When the pressure gage registers such a high pressure, it will thereforebe anln- 'dication for the operator to stop opening the trap door andpossibly even to close it partways until thecongestion of the trough hasbeen overcome. The fact that the congestion has been overcome will beindicated by a drop of the pressure, whereupon the operator may resumethe opening of Y the trap door in order to release further material intothe trough, which then is orderly conveyed into the storage bin.

The means I use and the manner in which I proceed for automaticallyoperating the trap door or a means equivalently releasing loose bulkmaterial,--so that the release of the material into a conveying airblast is controlled by the pressure of i said blast.will be exemplariiydescribed in the following in connection with Fig. 8.

For purposes of clarity in this description, the

generator G is presumed to deliver a direct-cur rent issuing from thepositive terminal thereof. One' branch of the current of said generatorcomprises the electo-magnet 63, which serves to actuate an armaturelever 64. The said armature lever is mounted upon the fulcrum shaft 65of a 5-pole' double throw switch 68, the knives of said switchcontacting with lugs 11., b, c, d, e, when in the normal position ofrest of Fig. 8, whereas they contact with lugs A, B, C, D, E, when theelectro-magnet or relay '63 is excited and attracts the armature lever64. Excitation of the electro-magnet is controlled by the mercurypressure gage 6|. The mercury column of said gage closes the circuit ofelectromagnet, when it is predeterminedly actuated by the pressure ofair entering in the direction of arrow 62. For that purpose twoterminals of the circuit of electro-magnet 63 enter upon the two legs ofthe mercury pressure gage at different levels 66 and 61: The level ofthe mercury when at rest is to a certain distance above the centerbetween the levels and 61, the amount of mercury in said legs and thedistance to which its average level is above the said center determiningthe pressure range at which control of relay 63 takes place, as willreadily be understood with those acquainted with this art after -aperusal of this exemplary showing. It is sufficient to state here thatwith the arrangement shown the circuit of the electro-magnet 63 is openwhen the gage registers substantially atmospheric pressure or less orwhen there is a high pressure, at which the air drives the mercurycolumn in the right leg of the gage to a point below the level 66. Themercury column closes the circuit of electromagnet 63 at intermediatepressures which cover the pressure range at which the air blastfunctions properly. When the mercury column registers substantiallyatmospheric pressure or less or an unduly high pressure, the switch 68is in the position shown in Fig. 8 and the generator current passesthrough mercury switch 41 to lug c of the switch, and through the switchby way of lug d to the armature of motor M and then back to thegenerator, and also through the switch by way of lug b to the field F ofthe motor, back through the switch by way of lugs a and e, and then to Ithe generator. .In this instance the motor is presumed to rotate in acounter-clockwise direction, so that the band 36 moves from the right tothe left, the trapdoor being closed. When the end of the trap doorengages upon lever 45, as it becomes closed, it breaks the current atthe mercury switch 41, so that the supply of current to lug c, whichfeeds both armature and field of themotor, is interrupted, the motorstops and the whole system is at rest.

The transmission between the motor and the sliding trap door is gearedto a low speed of movement of the trap door, so that the trap door opensat the proper speed in order to release the loose bulk material into theair blast at an average speed suitable for discharge into the deliverybuilding 53.

When the air blast is started, the .electric system is substantially inthe position subscribed just before, the switch 68 being in the positionshown in Fig. 8, but the circuit being open at the mercury switch 41,because the trap door is closed. The air blast drives the mercury ingage 6| out of equilibrium,- into a position where terminals Q6 and 61are connected, so that now the switch v68 is thrown into contact withlugs A, B, C, D,

and E.v Mercury switch 48 being closed, the current passes from thegenerator through said switch to the lug C, into the switch and fromthere on one side by way of lug D to the amiature of motor M and back tothe generator, proceeding substantially symmetrically to the waydescribed in connection with the position of rest of the switchyon theother hand it passes from lug B through the field F of the motor in adirection opposite to that in which it passed therethrough before andthen back through lugs A and E of the switch 6; to the generator. Thefield of the motor now being reversed, the band will travel to theright, and the trap door is being opened. The

- slowly released into the trough, the air blast blows out of the troughthe quantities of material thus released, and eventually, when fullyopened, the" trap door will release levers 46, so that the part of thecircuit of the motor, which serves to actuate the motor in a clockwisedirection is interrupted; thus the motor comm to a stop when loose bulkmaterial will bethe trap door is open. This state will be preserveduntil the pump is. stopped sothat the mercury column returns to itsposition of equilibrium, whereupon the electro-m'agnet 63 releases theswitch 68. The switch 68 drops into the position of Fig. 8, and the'trap is closed in the manner described before.

If the opening trap door releases too much bulk material so that thetrough becomes congested, the air pressure drives the mercury column. ingage 6! so high that the circuit of the electromagnet is interrupted at66; thereupon the switch drops into the position of rest shown in Fig.8, and the direction of rotation of themotor is reversed so that thetrap door is being closed. This proceeds until the air blast has removedthe excess loose bulk material in the trough, whereupon con-,

shown and it is arranged symmetrically. Again the container 1| merges atthe bottom with a trough 12, and at both ends of the trough I provideflange connections 13 and 14, one being connected to the air blastdeliveredfrom a pump or compressor, the other one to the deliveryconduit leading to a storagebin. On both ends of the container 1| arearranged above the trough similar compartments 15 and 16. In thesecompartments are coiled up the ends of a flexible plate 11 upon shafts,which may be rotated by the crank handles 18, arranged upon the outsideof said compartments. The flexible band 11 again slides upon suitablemeans on both sides of the conveyor 12, so that it closes the container1| towards the trough 12; but the band is provided with a transverseslot 19, upon which is superimposed, upon the bottom side of band 12, aplate 80. By means of slots BI and wing nuts 82, the plate may beadjusted lengthwise at will upon the band 12, that the free aperture ofslot 19 may be adjusted to any desired width. By manipulating one or theother handle '18, the slot 19 may be positioned at any point near thebottom of the container, or may be moved from the container into one orthe other of compartments 15 or 16. In this manner the point at whichthe loose bulk material contained in the consubstantially the wholelength of said container.

That shifting may be of particular use when the material is graded, orassorted in the container. A grading of the material, as it isintroduced into the .container, is brought about by providing thereinone or more transverse partitions like 9| and 92, extending from oneside of the container to the other, but extending only partways uptherein, thus forming bins which clear the blast conveying the loosebulk material, which enters through the inlet 26.

To those acquainted with the conveying of loose bulk material in theblast of a gas, air for instance, it is known that, as the speed of saidblast decreases, the heavier grain material drop is; the lighter grainmaterial later, and the finest dust is precipitated last, if at. all. a

In the container of my invention the air blast tainer is releasedtherefrom may be shifted along .tainer, behind partition travelssubstantially through the whole length thereof, and then the air iscirculated to' the rearofthe container where it leaves through thevacuum chamber 22. Thus I might arrange that the heaviest materialcarried by the air drops to the left of the partition 92 (Fig. 1), lightmaterial drops between the partitions 82, 9|, and the dust drops intothe bin in the back of the con- 9l. Into the last mentioned bin willalso drop the filters 24, when those filters are shaken.

As the band 36 is withdrawn from between the container 2| and the trough3|, the heavy loose bulk material to the left of partition 92 dropsfirst into the trough 3|. band comes into alignment with the bottom ofpartition 92, the compressor pump I may be stopped and the outlet 33 maybe connected to another receiving or storage receiver which is reservedfor the finer grain material which drops out of the bin. confronted bypartitions 92 and 9! as the band 36 is further withdrawn, after the pumphas been started again. In like manner the finest grain material or dustin the bin to the right of partition 9| may be withdrawn separately andmay be discarded if it is undesirable.

The number of partitions and the spacing of said, partitions from eachother are factors controlling the degree of assorting or grading broughtabout and may be greatly varied according to the material handled andthe useto which the said material is ultimately converted.

A crank handle like 18 may of course also be attached either to the endof shaft 4| or to the shaft'of motor M (Figs. 1 and 8).- In that casethe whole reversing circuit of the motor may be omitted, because thereversing may be done by thecrank, and when too muchof the loose bulkmaterial flows out of the container into the trough, the movement of thetrap doors 35 is temporarily stopped instead of being reversed. In thatinstance the electric circuit is consider- ,ably simplified, as wellunderstood by those acquainted with this art: It may then be reduced toan arrangement of the generator, motor, the pressure controlled switchGI, and mercury switch 48 in series.

. said current of air,

However, it will readily be understood by those acquainted with this artthat the control of the trap door may be brought about ina flner degreeof adjustment by the use of more complicated control circuits.-- Itherefore do not want to limit the protection granted to me by thispatent to the very control of the release of the loose bulk materialshown, nor to the method and means described in the specification andshown in the drawings, but reserve the right to make changes andalterations in the form of embodiment of my inventions, which do notdepart from the spirit and scope thereof.

What I claim is:.

1. The method of delivering loose bulk material from one container intoa second container, comprising directing a current of air' past thefirst container into the second container, releasing said material fromsaid first container into said released material being conveyed by saidcurrent-into the second container, and controlling said release inaccordance with the fluctuations of pressure set up in said current bythe material released 'thereinto.

2,. Means for transferring loose bulk material, comprising a vehicle, acontainer on said vehicle storing said material for transportation bysaid the dust which clings to v When the end of the said pump tovehicle, means sucking said material into said container, a valve forshutting on said sucking means relatively to said-container, a deliveryconduit underneath said container, means driving air through saidconduit, and means controlledly releasing said material from progressivepoints of said container into said conduit.

3. Means for transferring loose bulk material, comprising a vehicle, apump, a container on said vehicle, means connecting the intake of saidpump to said container, so that said material may be sucked intosaidcontainer, a delivery conduit connecting with various points of saidcontainer, means for successively releasing material from said pointsof. said container into said conduit, and means connecting the outlet ofsaid pump to said conduit, so that a current of air may be blown throughsaid conduit and said released material may be conveyed away thereby.

'4. Means transferring loose bulk material com prising a vehicle, apump, a container on said vehicle, means connecting the intake of saidpump to said container, so that said material may be sucked into saidcontainer, a delivery conduit operatively connected with the outlet ofsaid pump, a device actuated by the pressure of the air passing fromsaid pump into said conduit, and means operatively connected with saiddevice and releasing material from said container into said conduit.

5. Means for transferring loose bulk material comprising a vehicle, apump and. acontainer on said vehicle, means connecting the intake ofsaid container, so that said'material may be sucked into said container,a trough communicating with said container along the bottom thereof andcommunicating with the outlet of the pump at one end and outwardlyopening at the other end, a trap door extending longitudinally of saidcontainer and said trough, and a mechanism for gradually andcontinuously opening said trap door from one end of said container tothe other.

6. Means for transferringloose bulk material comprising a vehicle, apump and a container on said vehicle, means connecting the intake ofsaid pump to said container, so that said material may be sucked intosaid container, a trough comby material released into said trough andcollecting therein at one time, said means'controlling said mechanism.

'7. Means transferring loose bulk material comprising a vehicle, a pump,a container on said vehicle, means connecting pump to said container, sothat said material may be sucked into said container, a troughcommunieating with said container along the bottom ther'eof-andcommunicating with the outlet of the. pump at one end andoutwardlyopening at the-'other end, a trap door adjustably interposedbetween said container and said trough, a mechanism opening said trapdoor and releasing said material from said container into said trough,said material being conveyed out of said trough by the air circulatedtherethrough, and a presthe intake of said sure gage reacting upon theflow of air conveyed bysaid pump through said trough and operativelyconnected with and controlling said mechanism.

8. Means transferring loose bulk material comprising a vehicle, a pump,a container on said vehicle, means connecting the intake of said pump tosaid container, so that the said material may be sucked intosaidcontainer, a trough communicating with said container along the bottomthereof and communicating with the outlet of the pump at one end andoutwardly opening at the other end, a trap door adjustably interposedbetween said container and said trough, a motor opening said trap doorand releasing said material from said container into said trough, saidmaterial being conveyed out of said trough by the air circulatedtherethrough, and a pressure gage reacting upon the fiow of air conveyedby said pump through said trough and operatively connected with andcontrolling said motor.

9. In a means transferring loose bulk material, a container, a troughcommunicating with said container, a flexible trap door slidablyinterposed between said container and said trough, a com partment intowhich said door extends, and,

means in said compartment coiling up'said door when slid thereinto.

10. In a means transferring loose bulk matea trough communicating withflexible trap door slidably insaid container and said trough,

thereinto, and a mechanism predeterminedly propelling said'door betweena position in which it closes said container towards said trough and acoiled up position in said compartment.

11. In a means transferring loose bulk material,

a container, a trough communicating withsaid sure of said propelled air,and means controlled by said gage and opening and closing said door.

12. In a means transferring loose bulk material, a container, a troughcommunicating with said container, a door interposed between said'container and said trough and controlling the release of said materialfrom the former into the latter, a mechanism operating said door, a pumppropelling air through said trough and conveying said materialtherefrom, a gage measuring the pressure of said propelled air, andmeans controlled by said gage and opening said door at a predeterminedpressure of air and closing said door at pressures above and below saidpredetermined pressures.

13. In a means transferring loose bulk mate, rial, a container, apartition dividing said container into bins for different grades of saidmaterial, a trough communicating with said bins, and a door interposedbetween said container and said trough and successively opening saidbins towards said trough when operated.

14. The method of pneumatically discharging the contents of loose bulkmaterial from a container on a vehicle, comprising conducting a currentof air past a low part of said container, and successively opening saidcontainer at various points onto said current, so that continuouslyadditional material is released from-additional parts of said container.

15. The method of pneumatically discharging loose bulk material from aclosed container on a vehicle, comprising conducting a current of airpast a low part of said container, and progressivej ly opening said partof the container along a straight horizontal path, sothat additionalmaterial continuously drops into said current and is transmittedthereby.

16. The method of pneumatically discharging a container on a car,comprising conducting a current of air past the bottom of saidcontainer, and in chronological progression sectionally opening saidbottom, so that material from difierent sections continuously drops intosaid current and is transmitted thereby.

LUDWIG F. HOLLY.

